In the processing of crude oils, severe corrosion problems may be encountered when the crude contains noticeable amounts of organic acids, particularly naphthenic acids. Such problems are even worse when the crude oils as processed contain some salt water. Through acid exchange, salty crude oils which contain naphthenic acids may exhibit the severe corrosion characteristics of hydrochloric acid. When such oils are processed by normal distillation methods, the equipment used must be constructed of expensive corrosion resistant alloys. Conventional resolution of the naphthenic corrosion problem by neutralization with basic compounds such as sodium hydroxide, ammonia and calcium hydroxide, is not satisfactory because the neutralized acids are still corrosive and unstable, and often act as persistent emulsifying agents, giving rise to intractable emulsions, which give rise to more processing problems. Another problem for conventional refining processes is encountered when the crude oil contains appreciable amounts of sulfur and sulfur compounds which also leads to severe corrosion problems.
Accordingly, an object of the present invention is to decarboxylate the crude i.e., to convert the naphthenic acid contaminants found in the crude oil to non acidic compounds. Another object of the present invention is to provide a method for removing the sulfur found in the crude oil in the form of mercaptans, sulfides, hydrogen sulfide and cyclical compounds. Yet another object of the invention is to provide a continuous method and apparatus for removing acidic contaminants by decarboxylating the crude and also for removing the sulfur, and any solids, salts, water and other corrosive agents, to yield a clean, sweet oil eminently suitable for conventional refinery processes. Moreover, the present invention can effectively be used with any type of crude oil having oil-water emulsions stabilized by finely divided solid materials. These emulsions can be separated into an economically processable oil fraction which is low in both suspended solids, water, heavy metals, sulfur, naphthenic acids, salts and other contaminants, an ecologically acceptable waste water fraction, and, preferably, flocculated finely divided clean oil-free solids which can easily be disposed of.